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By G. Kelly

A new minerals engineering education programme is being developed in Australia which aims to provide tertiary institutions with a package of educationally sound, high quality courses for undergraduates, postgraduates and professionals. The programme is jointly funded by the Minerals Council of Australia (MCA) and the Department of Education Training and Youth Affairs (DETYA) and brings together academics from a number of leading Australian universities, each developing modules in their particular area of expertise. The University of Queensland (UQ) and the Julius Kruttschnitt Minerals Research Centre(JKMRC) are jointly responsible for modules in several areas including comminution, physical separation and circuit design and optimization. Other modules are being developed by the University of South Australia (with the Sir Ian Wark Centre), Curtin University and Murdoch University. The major challenge of the programme is to provide a high standard of education that is accessible to students who may be located at several different institutions and some of whom maybe a long distance from the primary course leader. Rather than taking existing course material and putting it ‘on the web’, the programme aims to improve on past teaching practice through creative pedagogy and the development of interactive multimedia learning resources. Communications technology is used in an unobtrusive way, and the World Wide Web is used to create a flexible, user-friendly learning environment rather than to facilitate delivery of content. This paper describes the instructional design template currently being used and results of early implementation trials with groups of local and remote students.

Jan 1, 2003

The validity of a steady state assumption made by Adams and Nicol (1986) in the modelling of the elution of gold from activated carbon was investigated. It is shown that the accuracy of the steady state approximation is dependent, not only on the magnitudes of the solution flow rate and reactor volume, but also on the lumped elution rate constant. Under the experimental conditions used by Adams and Nicol (1986) the steady state assumption was inaccurate. This could be circumvented in this instance by applying a rigorous general model which accounts for unsteady state behaviour in the solution and in the activated carbon to the experimental data.

Jan 1, 1997

By K. S. Rao, R. P. Tiwari, V. K. Shrivastava

ABSRACT: In this paper numerical simulation of jointed block mass behaviour obtained in an experimental study has been presented. Singh et al. (2002) conducted extensive tests on the jointed model materials with several joint configurations. The results of this experimental study were used to validate the strength behaviour of numerical block mass model developed using professionally available software. This software basically contains different kinds of material models. From the results of numerical simulation the existence of strength anisotropy was observed. The strength anisotropy so obtained has been compared with the experimental values reported by Singh et al. (2002). The anisotropic curves in both cases are U-shaped with flat base. They show good agreement in sliding mode of failure zone in which inclination ß (= 90° - ?) of joint set-I lie between 20° to 40° for all cases of interlocking. ZUSAMMENFASSUNG: In dieser numerischen Papiersimulation des verbundenen Blockmasse Verhaltens, das in einer experimentellen Studie erhalten wird, ist dargestellt worden. Singh et al. (2002) leiteten umfangreiche Tests auf den verbundenen vorbildlichen Materialien mit einigen gemeinsamen Konfigurationen. Die Resultate dieser experimentellen Studie wurden verwendet, um das Stärke Verhalten des numerischen Blockmasse Modells zu validieren, das mit professionell vorhandener Software entwickelt wurde. Diese Software enthält im Allgemeinen unterschiedliche Arten der materiellen Modelle. Von den Resultaten der numerischen Simulation wurde das Bestehen von Stärke Anisotrophie beobachtet. Die Stärke Anisotrophie also erreicht ist mit den experimentellen Werten verglichen worden, die von Singh et al. (2002) berichtet werden. Die anisotropen Kurven in beiden Fällen sind mit flacher Unterseite u-förmig. Sie zeigen gute Vereinbarung in gleitender Erscheinungsform des Ausfalls Zone, in der Neigung ß (= 90° - ?) von der Verbindung stellenSie Lüge zwischen 20° auf 40° für alle Fälle vom Ineinandergreifen ein. RESUME: Dans cette simulation numérique de papier du comportement joint de la masse de bloc obtenu en étude expérimentale a été présenté. Singh et autres (2002) ont effectué les essais étendus sur les matériaux modèles joints avec plusieurs configurations communes. Les résultats de cette étude expérimentale ont été employés pour valider le comportement de résistance du modèle numérique de la masse de bloc développé en utilisant le logiciel professionnellement disponible. Ce logiciel contient fondamentalement différents genres de modèles matériels. Des résultats de la simulation numérique on a observé l'existence de l'anisotropie de force. L'anisotropie de force ainsi obtenu a été comparée aux valeurs expérimentales rapportées par Singh et autres (2002). Les courbes anisotropes dans les deux cas sont en U avec la base plate. Elles montrent la bonne concordance dans le mode coulissant de la zone d'échec en lequel la inclination ß (= 90° - ?) du joint placez-Je le mensonge entre 20° à 40° pour tous les cas d'enclencher.

Jan 1, 2003

By S. Kahraman

The correlations between the modulus ratio and penetration rate of rotary and percussive drills were statistically investigated using the raw data obtained from the experimental works of different researchers. An inverse power law was found between the modulus ratio and the penetration rate of rotary and diamond drills. The penetration rate of rotary drills and diamond drills decrease with an increasing modulus ratio. The penetration rates of percussive drills increase with an increasing modulus ratio. There are significant linear correlations between the penetration rates of percussive drills and the modulus ratio. In one of the cases of percussive drilling, a strong correlation between the penetration rate and the modulus ratio was found for the rocks having a porosity value lower 1.23 %. It can be concluded that the modulus ratio might be a representative measure of rock drilling efficiency. However, further study is necessary to check the validity of the derived equations for other rock types. The effect of porosity on the correlations between the modulus ratio and penetration rate needs to be further investigated.

Jan 1, 2003

By J. H. Zietsman, S. Maharajh, J. Muller

In the chlorination process for TiO2 pigment production, blends of titania feedstocks such as ilmenite, synthetic rutile (SR), natural rutile, upgraded slag, and chloride-grade slag are reacted with coke and chlorine at a temperature of around 1000°C to form TiCl4 (the main product) and other waste metal chlorides. The TiCl4 is the main feed material for the TiO2 pigment-making process. Feeding different titania materials to the chlorinator affects the amount of coke and chlorine required for the process, the amount of waste generated, waste disposal costs, the amount of TiCl4 produced, and bed build-up rates. These factors influence the value of the feedstock. Generally, a higher TiO2 feedstock is more valued since less waste is generated and less reagents are consumed. To quantify the impact of different feedstocks on the chlorinator, a techno-economic model was developed to describe the chlorination process and estimate process variables at steady state. This paper describes the development of the model and studies in which the model has been used to quantify effects of using different feedstocks.

Jan 1, 2015

By S. Kwon

When an underground excavation is created near to an instrumented measuring location, deformation at the location increases. The characteristics of this deformation increase, as well as the duration of the influence caused by the adjacent excavation, is dependent on parameters such as opening geometry and measuring location. In this study, neural networks were applied to investigate the deformation increase and the influence of each parameter on the deformation change derived from extensometer measurements at the Waste Isolation Pilot Plant (WIPP) site in New Mexico, USA.

Jan 1, 1998

An efficient and portable mathematical model has been developed for simulating heat transfer in six-in-line slag-resistance-heating electric furnaces for smelting sulphide ores to produce base metals and platinum group metals. This model is a steady-state one relating furnace conditions and performances to various control and input parameters. Some transient effects occurring in electric furnaces are neglected for computation efficiency. This article describes the model development and modelling results. The present model is capable of predicting: (i) temperatures at various locations in a six-in-line furnace, such as slag bath, matte bath, solid charge, freeboard space, freeze lining, cooling water, and air gaps between solid material components, etc. (ii) freeze lining thickness, (iii)smelting rate, and (iv) heat loss rate, etc. A typical feature of the model is that it is easily portable to different application platforms and sufficiently efficient with execution times less than a few seconds. Therefore, it is possible to apply the model for online prediction and control of heat transfer and freeze lining thickness in industrial electric furnaces.

Jan 1, 2011

By V. Mathebula

Paper written on project work carried out in partial fulfilment of B. Tech (Mining Engineering) degree The purpose of this study is to establish whether to mine the Bottom of Pit (BOP)/TOB 4 reserve before the commencement of the Block Cave or whether this should be disregarded and the reserve be extracted at the end of the life of the Cave. The primary goal of this report is to investigate and propose a practical mining method to safely extract the reserve given the set constraints. This report quantifies the additional revenue the TOB 4 will contribute to Finsch?s overall NPV thus enhancing Finsch?s business case and strategically enhancing the SBP. Several underground mining options have been investigated. The proposed mining method includes the installation of a series of extraction tunnels below the TOB 4 reserve from 53 level, with a slot access tunnel system. Ground will be loaded by LHDs from the draw points and tipped into 50-ton dump trucks at a transfer point, from there the ground will be transported to 53 level No. 1groundpass where it will join the existing ground-handling system. Primary development is scheduled to begin October 2002 and last for a period of approximately 7 months until early April 2003.The production is broken into 4 phases. Phase 1 is scheduled to begin mid-April 2003. The final production phase will be completed by November 2005. The production scheduling has been designed in order to remain ahead of the Block 4 undercut in order to ensure stability and safety. Due cognisance was taken of the health and safety of all employees concerned during the design of the mining and ground-handling processes for the Bottom of Pit. As far as is reasonably practicable, the BOP was designed and will be constructed and equipped to provide conditions for the safe operation of machinery and a healthy working environment for people underground. Relevant requirements of the Mine Health and Safety Act regulations pertaining to mining operations have been identified and adhered to during all phases of the design process.

Jan 1, 2004

By S. J. Ramokgopa

The development of the modern State and the growth of capitalism involves a complex process of interaction between cross-cutting structural dimension: first between politics and economics and, second, between market and hierarchy. Central to such developments are political economies of scale. Mineral specialization in the Third World developed within the framework of an international extension on oligopolistic structure of the advanced capitalist economies of Western Europe and North America. Up to the late 1960s, the world mineral and metallurgical industry was closely controlled by a handful of Western mining and industrial groups. To the extent that, foreign control of the mining sector was seen in the Third World producing countries both as the essence of foreign domination and as its major symbol. In some newly industrializing countries, the State took a more direct role in tying the economy and society together. Central to this process was the growth of large-scale finance capital. From early 1959to the mid-1970s, metal consumption in industrial countries expanded well beyond their domestic mineral endowments. And a free access to Third World minerals was a major element of the economic dynamism of these countries throughout that period. With the change in the characteristics of international investment, Africa has become less important as an outlet for capital exports of European countries. Actually, the African continent now receives only a very minor share of direct foreign investments of Western enterprises. International political economy is concerned first of all with the relationship between the economic and political domains across territorial boundaries. Second, attention should be drawn to the role of the State as the focus of decision-making in a system of competitive States, that is in turn, interdependent with a trans-national market economy in which mining and metallurgy are essential activities that affect the politics of the State, and how this in turn, rebounds on the politics of the international system. Understanding the role of the State must go beyond the glib pronouncements on the ?national interest?. How, and whose interest, the ?national interest? is determined, is precisely the problem. This implies a third theoretical problem that must be addressed: the linkage between the domestic and international domains (or levels of analysis), given that political-economic processes clearly cut across the lines of political decision-making constituted by the institutional structures of the State. Situating the State and economic interests within this vast ?state-society? complex that we call the global order will be a crucial problem for any theoretical approach that involves mining and metallurgy.

Jan 1, 2002

By A. Burger Pintér

To be meaningful the sharing of ideas about the National Environmental Management Act (NEMA) and social issues within the context of Mining and Metallurgy (M&M) requires an honest scrutiny of the M&M/social environment relationship, both past and present. It is not a secret that this relationship has been and is fraught with difficulties. Thus from all perspectives (M&M, society and environmental and social consultants) such a dissection, that highlights the realities, both good and bad, is uncomfortable. For this section of the colloquium to have any value, the honest but difficult approach needs to be taken.

Jan 1, 2000

By J. Roodt

Paper written on project work carried out in partial fulfilment of B. Eng (Metallurgical Engineering) degree This work was done to characterize the leaching of a uranium containing pulp processed by a South African producer to identify parameters that could be adjusted to increase the extraction of uranium in the existing circuit. Batch leach tests were used to characterize the leach properties and especially the influence of the oxidant concentration on the leaching achieved. It was found that relatively high extraction could be obtained even at room temperature by using a high liquid-to-solids ratio and that increasing the oxidant concentration significantly improved the leaching of the uranium minerals.

Jan 1, 2003

By J. A. Cruise

From 27th to 29th September, The South African Institute of Mining and Metallurgy held a Colloquium on Equipment Alternatives in Underground Mining in Johannesburg. The Colloquium, which was highly successful, was held concurrently with the 1988 Electra Mining Exhibition. Particle characterization The Fourth European Symposium on Particle Characterization is to be held in Nirnberg, West Germany, from 19th to 21st April, 1989.

Jan 1, 1988

By R. E. Robinson

A novel variation of the GYPCIX process for the treatment of the acid mine effluent water from Grootvlei is described, in which a number of valuable by products can be obtained and the product water can be used for a variety of different purposes. A conceptual case study is presented in which the important cost parameters are described and certain critical path activities are indicated in order to derive a Return on Investment evaluation according to methods previously published. The study indicates that the treatment costs can be dramatically reduced, provided that proper utilization of the by products is taken into account. There are many possible uses for the water. However, by far the most advantageous contribution to the RDP and the best return on capital is derived if the water is used to establish small-lot farming activities providing work opportunities for thousands of people and contributing several hundred million Rands to the GDP. Vastly improved social conditions will be generated in an area of Gauteng that is in danger of rapid deterioration and a contribution will be made to maintaining mining activities in this area. The environmental impact is positive.

Jan 1, 1998

Like it or not, CPD is upon us. As from 1 January 2006, all registered engineering professionals, i.e. professional engineers, professional engineering technologists, professional certificated engineers and professional engineering technicians, were required to undertake CPD in order to keep their professional registration current. The rules regarding CPD have been gazetted under Government Gazette No. 28328, Board Notice 131 on 23 December 2005, and they also appear on the ECSA website?www.ecsa.co.za. For the convenience of our members they are reproduced in full in this issue of the SAIMM Journal.

Jan 1, 2006

By B. J. du Plessis

Automation of the conventional grinding circuits of Palabora Mining Company (PMC) required that adequate instrumentation and a control system had to be put in place, after which extensive testing had to be done to evaluate different grinding control strategies. The objective was either to optimize the particle size from the grinding circuit, or to increase milling circuit throughput while maintaining particle size at existing levels. Prior to automation of the process as described below the circuits were controlled manually. No on-line information on cyclone feed densities, cyclone feed flow or cyclone overflow particle size was available. This type of control relied heavily on interpretation of the process parameters by the operator and on his ability to make informed decisions on what the set points should be. An integral component of the automation process was the installation of a SCADA package (SysCad SDX) for implementing the on-line control strategy. A self-correcting model for prediction of cyclone particle size was developed and implemented on the SDX. The model is calibrated using values from the particle size analysers while they are operational. If the particle size analysers choke or fail for any reason, the model continues to provide a good estimate of the particle size. This technique ensures that a continuous particle size indication is available compared to the intermittent reading from the instrument. The continuous signal allows particle size to be used as a process variable for control purposes. A strategy was developed and implemented which allows for the production of a controlled grind size from the conventional milling circuit to the flotation circuit. The grinding control strategy allows for the control of particle size from the individual cyclone overflows. This strategy allows the operator of the process to increase or decrease production rate by specifying a coarser or finer grind size required for flotation.

Jan 1, 2001

By C. Kasatuka

Globalization creates investment opportunities for enterprises around the world. Attracting foreign investment has been a key challenge for economic growth in developing countries. Corruption, political instability, armed conflict, and other internal problems affect foreign direct investment (FDI) inflows negatively. A framework of criteria provides a basis for comparing non-commercial risk (NCR) among twenty-three mineral economies. Countries competing for foreign direct investment inflows are ranked from least to most risky. This study compares Inward FDI Performance Index (IND) with NCR ratings in developing countries and shows that risk is increasingly mitigated by means of appropriately structured insurance. Given the option for countries with similar mineral potential, investors will generally invest in the country that offers lower non-commercial risk. Keywords: foreign direct investment, non-commercial risk, developing countries.

Jan 1, 2006

By D. A. Bruce

The paper describes the construction of 5 plugs to resist high water heads at depth within the South Deep Gold Mine, Randfontein, South Africa. A total of 20 segments were involved to create these plugs, which were 7.5 m long at the 58 Level and 6.25 m long at the50 Level. Emphasis is placed on the QA/QC and verification methods, which were developed and governed all phases of the work, from initial rock preparation and pregrouting through to the final grout tightening of the rock/plug interface and the surrounding rock. This paper is one in a series of papers detailing other aspects of the project, which was constructed largely between May 2001 and August 2003.

Jan 1, 2006

By P. A. Olubambi

The leaching of zinc and copper from Nigerian bulk sulphide ore with sulphuric acid in the presence of hydrogen peroxide was studied. The aim of the study was to investigate the effectiveness of hydrogen peroxide as an oxidant for the sulphuric acid leaching of zinc and copper from a complex sulphide ore. Distribution of elementals within the various particle sizes was initially determined by ICP-OES and XRF to provide a basis for explaining the dissolution process. The effects of concentration of hydrogen peroxide, particle size, stirring speed, and leaching time at a constant temperature of 298K were studied. There were variations in elemental and mineralogical composition within the different sizes. The concentrations of zinc and copper reduced as particle size decreased while silica, sulphur, iron and lead contents increased. Dissolution results showed that the leaching rate of copper was lower than that of zinc. The highest recoveries of zinc and copper were obtained at a leaching time of 180 minutes, stirring speed of160 rpm, particle size of 75 µm and a concentration of 1M H2SO4/1MH2O2. It was observed that the leaching rate of zinc and copper increased with increasing hydrogen peroxide concentration. Increased stirring speed had a negative leaching effect as it promotes hydrogen peroxide decomposition. Keywords: Nigerian sulphide ore, zinc, copper, hydrometallurgy, sulphuric acid, hydrogen peroxide.

Jan 1, 2006

By D. J. Greeff

By making use of genetic programming, empirical models for metallurgical processes can be evolved that are more cost-effective than models determined by means of classical statistical techniques. These methods explore populations of candidate models assembled from sets of variables, parameters and simple mathematical operators, and do not require explicit specification of model structures. The application of the proposed strategies is illustrated by means of a case study pertaining to the leaching of nickeliferous chromite ores. Modelling of the nickel and cobalt extraction from the ores yielded models of similar accuracy compared to those obtained by non-linear regression and artificial neural networks. However, in the case of the iron extraction from the ores, the genetic programming model was significantly more accurate than both the regression and neutral network models.

Jan 1, 1998

By R. C. W. Webber

Mining up to depths of 5 000 m would be a world first and, accordingly, no previous experience in the determination of acceptable heat stress limits, criteria or indices is wholly applicable. However, some South African gold mines are already operating at depths beyond 3000 m and much of the knowledge gained in reaching and working at such depths will be helpful in making adequate provision for acceptable environmental control at the greater depths being contemplated. Accordingly, it is necessary to take cognisance of the industry?s experience in deep-level mining and of standards and regulations already established in South Africa and elsewhere in order to ensure acceptable working conditions and control standards, that compare favourably and defensibly with those in other mining industries. The local and international use of heat stress limits, criteria and indices were investigated as it was necessary to determine to what extent any other indices, limits or criteria would be applicable to South African deep mine conditions. In addition, it was necessary to establish whether there was a single heat stress index that could be used for South African ultra deep mining conditions. It was found that an appropriate combination of heat stress indices would be required in planning for and ultimately controlling thermal conditions in ultra-deep mining. The depths being contemplated and the concomitant potential heat hazard present too great a risk for reliance on a single environmental component of heat stress, such as wet-bulb temperature at present in common use locally. The study recommends that a heat stress index, preferably Air Cooling Power (ACP), be used to design an ultra deep mine?s ventilation system and that wet-bulb temperature be used to monitor and control the system once it is implemented.

Jan 1, 2003